Gripping the Control Column...
When I did my QXC, one of the legs was from Blackpool to the North Wales Coast, and in the Piper Tomahawk I decided to trim the thing so that it would fly hands-off, which it did for most of that route.
I now fly a C172 with rudder trim, which if set to give a central Ball, needs about 2 ounces of pressure on the right aileron to stop the aircraft doing a 60 mile radius turn.
So in all cases a strong grip is not required, and if you ever get to fly with an auto-pilot, you will wonder why the Control Column is needed at all..!
.